Selective sorption of nickel and cobalt from sulphate solutions using chelating resins

Four chelating ion exchange polymeric resins were tested to remove Ni and Co from synthetic solutions simulating pressure acid leach liquor. The goal of this work was to select a commercial resin capable of extracting nickel and cobalt with high selectivity. The resins behavior regarding nickel and cobalt sorption and desorption was described and some parameters were discussed. Nickel and cobalt sorption was studied according to some experimental parameters, such as time, initial metals concentration, Ni/Co concentration ratio and pH of the aqueous solution. The nickel and cobalt sorption results evaluated in a preliminary basis were very promising. The four commercially available ion exchange polymeric resins, Dowex M4195(R), Amberlite IRC748(R), Ionac SR-50 and Purolite S930(R), presented very peculiar features concerning selectivity and each of them seemed to be efficient on nickel and cobalt sorption under certain experimental conditions. Dowex M4195(R) showed the best results for nickel and cobalt selective sorption from acid liquors, since nickel and cobalt were equally recovered, in all pH range, with small influence of other elements. Even in lower pH, such as pH = 1, Dowex M4195(R) had the best performance for nickel and cobalt sorption. Amberlite IRC 748(R) also presented very promising results and further testwork would appear to be worthwhile. (C) 2004 Elsevier B.V. All rights reserved.